What is a gravity filter?
A gravity filter sits outside of the pond and is fed water by a pump where it enters the filter and flows through the filter media under gravity and returns to the pond. These filters must be positioned slightly higher than water level to enable its return under gravity. Gravity filters are the most efficient and effective because they have a larger amount of filter media and higher oxygen availability for bacteria than other styles. Gravity filters are suitable for all size ponds. Oase Biotec and Clearpond Biosteps are examples of gravity filters.
